Steam shovel



Jan.. 5, 1932. Q WV WALLlS 1,840,002

STEAM SHOVEL Original Filed Nov. 20, 1928 f. 0 7L i y 4 [/:1- 1 a n M r// /2 3 F/G. 4 8 'ff/6.6. /4 /3 4 /A//l// F/ 5. 47 4g @2 Ww 5j Www/5.

Patented Jan. 5, 1932 CHARLES WILLIAM WALLIS, OF TORONTO, ONTARIO, CANADA STEAM SHOVEL Application led November 20, 1928, Serial No. 320,723. Renewed ctober 13, 1931.

My invention relates to improvements in steam shovels, and the object of the invention is to devise means for increasing the cutting speed and power of the shovel, particularly when used in hard clays and like substances, thereby minimizing the leverage required by the-shovel when filling, and it consists essentially of the arrangement and construction of parts as hereinafter more particularly explained.

Fig. 1 is a side elevation showing the main beam ofthe steam shovel excavator, the shovel scoop and the connecting mechanism.

Fig. 2 is an enlarged sectional detail taken through the cutting edge of the shovel scoop and through one of the cutting teeth thereof A Fig. 3 is a side elevation of a valve mechanism for controlling the air supply for operation of the cutting teeth of the scoop.

Fig. 4 is a sectional plan view taken through the tooth support and showing the tooth in full taken on line 1 -4 Fig. 2.

Fig. 5 is a view similar to Fig. 2 showing means whereby the pressure of the tooth against the material to be lifted controls the air supply for actuating the tooth vibrating mechanism.

Fig. 6 is a detail of an alternative form of cutting tooth.

Fig. 7 is a view of the parts shown in Fig. 5 taken at right angles thereto.

In the drawings like characters of reference indicate corresponding parts in each figure.

1 indicates the main beam of a steam shovel which is pivotally mounted on the platform 2 in the usual manner. 3 is a movable beam operating in the main beam 1 to the lower end of which is mounted a shovel scoop 4, the mechanism being operated by the usual tackle 5. 6 is the bottom wall of the bucket to the forward edge of which is secured casting 7 forming the 'main support for the cutting teeth 12 which extend along the front edge of the bottom wall 6 in the usual manner at suitably spaced apart positions.

In the castings 7 are formed a series of cylinders 8 in each of which operates a pneubucket. The tooth l1 tapers inwardly as in- 60 dicated at 11x and terminates in a cylindrical shank 12 extending through the bore 10 and projecting into the cylinder 8 and it carries the lip 11 to prevent accumulation of impacted dirt entering the space between the relatively moving varying surfaces of the part 7 and part 11, the said bearing surfaces being kept cleared and oiled by the exhaust air from the cylinder 8 escaping through duct 22 and the space between the moving parts 11 and 12, the said exhaust air carrying a current of entrained oil for lubricating purposes.

The shank 12 is provided with a slot 14 engaged by a pin 13 in the main support 7 whereby the longitudinal movement of the tooth is limited.

15 is an air supply pipe leading into a maniand 21 into the cylinder 8 at each side of the 90 piston 9.

22 is an exhaust duct leading at one end from the valve chamber 18 in proximity to each end thereof and entering at its opposite end into a channel 23 surrounding the bore l0 and Shanks 12 of the tooth 11.

Air is fed through the pipe 15 so as to operate the piston 9 reciprocating it in the cylinder 8 to have a hammering action upon 100 15 s nchronizes w1th the loading operation of the ucket.

24 is the main power shaft connected by a clutch 25 to a hoisting drum 26. 27 is a clutch lever mounted upon a bracket 28 and provided with a fork 29, one arm of which is extended and provided with a slot 30.

40 is a rocking valve mounted in the casing 41, the end of the valve being provided with an arm 42 from which laterally extends a pin 43, such pin fitting into the slot 30 of the lever 27.

It will thus be seen that when the clutch lever 27 is operated to engage the clutch so that the bucket hoisting mechanism operates the same movement of the lever rocks the valve 40 so as to carry it to the open position and permit air to feed through the pipe 15 to the cylinder 8 for operating the teeth 11. When the hoisting operation is com lete the lever 27 is swung in the opposite irection, thereby simultaneously throwing out the clutch and closin the Valve 40 so as to cut oil air from the pipe 15.

It will be understood that during the eX- hausting operation of the valve 19 the exhaust air passes through the duct 22 into the channel 23 and passes outward through the interspace between the teeth 11 and the support 7, thereby serving to blow out any dirt which may tend to enter into such interspace during the operation of the device.

Referring to Fig. 5. In this ligure I enlarged the bore 10 as indicated at 45, the shank 12x of the tooth 11 being correspondingly enlarged as at 46 to iit such enlarged bore portion. The enlarged portion of the shank 46 is recessed at 47 longitudinally to form a byass. p The inlet duct 17x corresponding to the duct 17 of Fig. 2 leads into the enlarged bore portion 45 to feed the air into the recess 47.

48 is a. duct leading from the enlarged bore portion 45 to the inlet port 49. 50 and 51 are exhaust ports, and 52 an exhaust duct. 53 is a powerful compression spring surrounding the shank 12X and bearing at one end against the inner end of the recess and at the opposite end against an adjustable nut screwed onto the shank so as to regulate the resistance of the spring.

The spring 53 is adapted to retain the cutting edge of the tooth normally in the advanced position and the air pressure cut olf at valve 47 and the piston inoperative except when under pressure due to the forward movement of the scoop into the resisting material. The spring is then compressed by such forward pressure movement of the bucket against said resisting material and will add the resultant compressive spring stress to the effective percussion action of the air hammer formed b the piston 9.

As the tooth 11 is orced inward by pressure against the material to be lifted the bypass 47 is carried back to connect the duct 17 and thc duct 48 to permit the intiowing air to pass to the inlet port 49 of the feed valve. When the pressure on the tooth is relieved the by-pass returns to its normal position cutting off the air supply to the feed valve.

It will thus be seen that the tooth will not be vibrated except when the resistance to the cutting edge is suiiicient to compress the spring 53 and therefore when workino' in soft material the pressure on the toot is then not sufficient to compress the spring rendering the feed valve inoperative, and thus economizing air when working in soft material and acting as a selective device to effect the action of the cutters only when the resistance to the cutting action of the scoop requires it.

`When hard substances are encountered I employ a tooth such as illustrated in Fi 6 in which the tooth edge is provided wit a central spike 44 which is driven into the hard substance to break it up preparatory to being engaged by the body of the tooth.

From this description it will be seen that I have devised a very simple automatic device Which will serve to increase the cutting action of the shovel scoop 4, the teeth 11 vibrating so as to cut into the comparatively hard substance, such as soft rock or hard clay, as the front edge of the scoop engages therewith, tending to break it up and thereby permit the scoop to pass more easily through such substance during the filling of the scoop.

What I claim as my invention is:

1. In a steam shovel, the combination with the scoop provided with the usual cutting edge, of a member secured to the scoop along the cutt-ing edge thereof provided with a series of cylinders and provided with bores extending forwardly therefrom to the forward edge of the lmember, a tooth mounted in each bore and projecting into the cylinder at its inner end, a piston operating within the cylinder, means for feeding air into the cylinder to reciprocate the piston against the rear end of the tooth, a feed valve for controlling the feed of air into the cylinder at each end of the piston, a main supply for feeding air to the feed valve, a controlling valve for supplying air to the feed pipe, aclutch mechanism controlling the operation of the scoop provided with a clutch lever, and means operated by the clutch lever for opening and closing the control valve.

2. In a steam shovel, the combination with the scoop, controlling clutch and clutch lever,

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of a series of teeth mounted in the front edge of the scoop to reciprocate longitudinally, a

pneumatically operated mechanism for reo ciprocating the teeth, and means for supplying compressed air to such mechanism operated simultaneously by the movement of the clutch lever to engage or disengage the clutch mechanism. 3. An attachment for a steam shovel scoop comprising a casting attachableto the front or cutting edge of the scoop, a series of longitudinal movable teeth extending forward from the casting, and means for automatically vibrating the teeth to increase the cutting effect as the cutting ed e engages the mate rial toward the orwar or filling movement of the scoop. 4. In a tooth for a power shovel dipper, a body portion ada ted to be rigidly secured to the forward e ge of said dipper and to. form in usual manner a partof such edge including the excavating and loading func-4 tions thereof, said bod portion having a 1ongitudinal bore exten 'ng rearwardly from the forward end thereof, a shouldered point projecting forwardly from said body portion, said point having avrearwardly projecting integral shank, reciprocably mounted in said bore, meansl to limit forward movement of said point, and means for strikin impact blows against the' end of said sha 5; A power shovel dipper having a pluralit of teeth secured to the cuttin edge thereo and forming a part of such e ge including the usual functions of said edge and teeth, one or more of said teeth having a reciproca tory point, and means within the body of said tooth, for imparting blows'to the rear end of said point. 4 CHARLES WHLIAM WALLIS. 

